The Ransomware scans your data files and encrypt them so that they are unusable. When the infection has finished encrypting your data it will display a ransom screen that explains how you can pay the ransom and decrypt your files. It has a 24 hour timer built into the application that will increase the ransom amount each time it hits 0.
Read more here – http://www.bleepingcomputer.com/forums/t/546749/new-file-encrypting-ransomware-called-cryptographic-locker/